lytica, the pathogenic organism of a pernicious form of enteritis seen in the mole, through its various stages, and showed that the reproductive phase differed considerably from that of Coccidium schubergi. This research, even more than the others, involved protracted and continuous observation, and it is regarded by zoologists as being, even for Schaudinn, an exceptionally brilliant piece of work, but it is one that is somewhat beyond the scope of this paper. It may be noted, however, that Schaudinn believed that some of the appearances observed by him in this coccidian might explain certain phenomena in the development of tumours.
At the little village of San Michele, Schaudinn found abundant clinical material for his tropical work. One of his first studies there was undertaken to define the exact zoological position of the malarial parasites; and as a result, they were ultimately placed by him in the sub-order Hsemosporidia, and further divided into three species, Plasmodium vivax, Plasmodium malariae, and Plasmodium immaculatum. The latter term being, however, found to be preoccupied, was afterwards changed to falciparum, and that classification is now accepted, and is the familiar arrangement which is followed by most authorities. Almost the whole of the malarial work published by Schaudinn referred to the first variety, that of benign tertian. He showed that relapses in this infection were due to parthenogenetic reproduction of macro-gametes which had persisted in the blood, and which, owing to their abundant store of cytoplasm, outlived all other forms. He stated that the familiar signet-ring form was characteristic of future schizonts, that it was due to the formation of a vacuole, that it was designed to increase body surface and, thereby, nutrition, and that no ring stage was observable in future sporonts. The latter, in consequence, grew slowly, and their sex had time to be differentiated, and was deter-
